This invention relates generally to adjusting devices, and in particular to a gear screw adjuster used in connection with motor vehicle headlamps.
As the design of vehicles, automobile, and light trucks in particular, has evolved, headlights have continually been reconfigured to improve the aerodynamics of the front end of the vehicle. Modern headlights are designed so that their lenses follow the contour of the vehicle to provide an aerodynamically efficient exterior surface. However, adjustment of these headlights must still be performed in order to provide an optimal beam of light and to prevent the aiming of light beams toward oncoming vehicles. Automotive manufacturers' demand for aerodynamically efficient headlight designs has lead to modular designs requiring the headlight adjustment mechanism to be located within the interior of the engine compartment so that adjustment can be easily performed without removing any exterior trim pieces. Thus, the constraints of the installation area and the demands of the automobile manufacturers for aerodynamic headlight designs make it desirable to provide an adjuster for use with the aerodynamic designs that is adjustable from inside the engine compartment using ordinary tools, and translates rotational motion of the adjusting part into adjustment of the reflector within the headlight assembly. There are a wide variety of prior art adjuster devices including, among others, the devices disclosed in U.S. Pat. Nos. 5,707,133 and 5,214,971 to Burton, the inventor of the present invention, the disclosures of which are incorporated herein by reference.
As disclosed in FIGS. 17 and 23 of U.S. Pat. No. 6,247,868, the disclosure of which is incorporated herein by reference, automotive lamp assemblies used as headlights typically comprise several basic parts: a support frame, a reflector, a lens, a bulb, and one or more adjusters. The support frame houses the reflector and the bulb on a pivotable mounting to allow the aim of the light to be adjusted using the adjuster. The lens seals the front of the assembly to protect it from the elements assailing the front end of the vehicle and provides an aerodynamic shape and attractive appearance. Traditionally, fixed and moveable ball joints have engaged the headlamp reflector. Actuating the moveable ball joint would result in altering the angle of the headlamp reflector by pivoting the headlamp about the fixed ball joints. In certain variations, two moveable ball joints are used to enable vertical and horizontal aiming of the headlamp.
In some instances, an aiming or gear screw replaces the moveable ball joint. With the screw assembly, the reflector mounts inside the housing on a gear screw assembly and is adjustable horizontally and/or vertically using adjusters that interface with the reflector by moving the gear screw. One such a screw assembly is disclosed in U.S. Pat. No. 5,444,603 to Otsuka et al. In order to securely hold the headlamp in the desired position, additional parts must be added to the aiming screw. As shown in FIG. 10 of the Otsuka Patent, a push-on fixer 10 is added to the aiming screw 20 after the screw 20 is inserted through the headlamp housing 1. Using a push-on fixer requires steps in addition to merely inserting the screw through the headlamp housing.
The Otsuka Patent also discloses the use of an O-ring 9a and plastic washer 96 or wave washer 8 to attempt to effect a seal between the headlamp housing 1 and the flange 24 of the screw 20 to control screw torque, and to control axial screw backlash. Such a configuration places the O-ring and washers in facial compression, the amount of which will very as a result of the individual part tolerances. Such variations in facial compression has been found problematic in that it can cause wide variations in screw torque and can result in inadequate sealing.
Accordingly, the need exists for a compact gear screw adjuster assembly that can be securely retained in a wall or other structure of the headlamp housing, can be adapted for use in connection with various headlamp housing and headlamp reflector designs, is more efficient and cost effective to assemble to the headlamp housing, and reduces the sealing problems associated with facially sealing O-rings. Of course, the present invention may be used in a multitude of non-automotive lamp situations where similar performance capabilities are required.